The aim is to identify and evaluate potential health hazards in the environment from exposure to chemicals by an in-depth search of the literature. The mechanism of action of the toxicant is the ultimate goal of this endeavor. Activities include compiling toxicological data for inclusion in data base records and profiles of chemicals identified in waste dumps throughout the United States; and collecting and documenting carcinogenicity information for the NTP Annual Reports of Carcinogens. Other areas of interest include chemical/chemical interactions and chromosome breakage and/or sister chromatid exchange in human cells.